The intent of this project is to study the corticotropin releasing hormone (CRH) mRNA distribution in immune challenged lewis and fischer rats. Abnormalities in central secretion of CRH have been correlated with the pathophysiology of several diseases such as arthritis, allergic encephalomyelitis, lupus erythematosus, major depression, anorexia nervosa, Alzheimer's disease, and chronic fatigue syndrome. Hypothalamic CRH inhibits vegetative behaviors that are thought of as adaptive to stressful situations such as feeding, growth, reproduction, and sexual behavior. The differential distributions of CRH receptors are mapped in three-dimension in the brain providing more insight of the mechanism how the difference in hypothalamic CRH expression and regulation has a functional role in regulating the inflammatory response as suggested by genetic linkage analysis.